Collapsible tube



Oct."9, 1945. R. K. OSTRANDER 2,386,498

COLLAPSIBLE TUBE Filed Sept. 1, 1943 2 Sheets-Sheet l TEL :1- ;L.

INVENTOR ATTORN EY Oct. 9, 1945. R. K, OSTRANDER 2,386,498

COLLAPSIBLE TUBE a v /f 2 NNNNNN OR Patented Oct. 9, 1945 UNITED STATES PATENT OFF-ICE Robert K. Ostrander, South Orange, N. J. Application September 1, 1943, Serial No. 500,800

g Claims.

This invention relates to collapsible tubes and methods for the manufacture thereof. The ln-- vention relates particularly to collapsible tubes made of non-metallic materials such as paper or plastics or combinations thereof.

According to the present invention I provide a collapsible tube consisting of a cylindrical tubu-' lected for purposes of illustrationis shown in the accompanying drawings in which:

Figure 1 is a side elevation of the finished tube.

Figure 2 is an enlarged vertical section through the upper end of a tube in process of assembly, showing the forming tools used in the assembling operation.

Figure 3 is a similar view showing a second stage in the assembling operation.

Figure 4 is a similar view showing a third stage in the assembling operation.

Referring to the drawings, the tube comprises a cylindrical tubular blank I of the desired length and diameter. The said tubular blank may be wound either spirally or convolutely from suitable material and sealed along spiral. or longitudinal seams as the case may be, or may be formed of seamless tubular material. As materials for such tubular blank I may use paper or plastic materials or combinations thereof, but I prefer to use a tubular blank made in accordance with the disclosure of my copending application Serial No. 450,615, filed July 11, 1942.

In the assembly of a collapsible tube according to my invention, a tubular blank as above described is placed on a cylindrical mandrel, said mandrel comprising two parts, a cylindrical plunger 2 and an outer cylindrical sleeve 3 which is slidable longitudinally of the plunger. A thin annular ring 4, preferably of a strong material which is resistant to deformation when subjected to heat and pressure is then placed within the upper end of the tubular blank, resting on the upper surface of the sleeve 3, the outside diameter of the ring being approximately equal to the inside diameter of the tubular blank and the inside diameter of the ring being approximately half the inside diameter of the tubular blank. After the ring 4 is in place, the upper end of the tubular blank is folded inwardly over the ring 4 as shown in Figure 2, the inwardly folded portion extending at right angles to the axis of the tube.

A premolded shoulder and neck unit 5 of suitable thermoplastic material such as cellulose'acetate is now placed on the plunger 2, the said plunger being provided with an elongated spindle 6 adapted to fit the passage 1 which extends longitudinally of the neck 8. Preferably the neck is threaded, asillustrated, to receive the conventional internally threaded closure cap (not shown). The bottom surface of the shoulder as premolded is provided with a depending annular flange 9 having a diameter less than the inside diameter of the ring I, but greater than the inside diameter of the inwardly folded portion of the tubular blank (Figure 2).

A forming die I0 is alsoprovided, said die having a large cavity ll having a conically tapered surface i2 conforming to the conically tapered shoulder portion of the unit 5, and having a smaller cylindrical cavity l3 of a diameter sufficient to fit loosely over the threaded'neck 8 without touching the same. The inside diameter of i the large cavity H is approximately equal to the outside diameter of the tubular blank, so as to engage the same snugly as shown in Figure 2.

Starting with the parts of the tube assembled as shown in Figure 2 and withth'e plunger 2, sleeve 3 and die ill in the positions illustrated therein, the sleeve 3 is first moved upwardly as shown in Figure 3 to move the end of the tubular blank into th cavity H and to clamp the inwardly folded end of the blank and the ring 4 tightly against the under surface of the shoulder. At the same time, such movement causes the inner edge of the inwardly folded portion of the tubular blank to be folded downwardly over the inner edge of the ring 4 by the annular flange 9.

During such movement of the sleeve 3 the plunger may either remain stationary or may be moved upwardly with the sleeve as shown in Figure 3. As soon as clamping pressure is applied, however, and whil such pressure is maintained, the plunger 2 is moved upwardly as shown in Figure 4. The upper surface of the plunger adjoining the spindle 6 is tapered conically at H, the base of the conically tapered portion having a smoothly rounded curve l5 merging into the horizontal portion 16. As the plunger moves upwardly, the conical portion engages the lower edge of the annular flange 9, forcing it outwardly, gradually folding the flange and the edge of the tubular body around the edge of the ring 4.

Preferably the plunger Z-is heated, a thermostatically controlled heating element (not shown) being preferably used to maintain a temperature merely sufficient to soften the thermoplastic material and render it pliable, but without causing the same to flow freely. A temperature of approximately 150 is Suitable for this purpose.

Thus, in the finished tube the depending flange 9 is bent outwardly under the ring I to clamp the ring against the shoulder, thereby seeming the inwardly folded portion of the tubular blank between the ring and the shoulder, and to clamp the end of the tubular blank against said shoulder, thereby securing the end of the blank and increasing the security of the holding action.

It will be understood that the invention may be variously modified and embodied within the scope of the subjoined claims.

I claim as my invention:

1. A collapsible tube comprising, in combination, a cylindrical tubular body, an annular ring, and a premolded shoulder and neck unit, said ring being within said tubular body and having an outside diameter substantially equal to the inside diameter of said tubular body, one end of said tubular body being folded inwardly over said ring, said premolded shoulder and neck unit having a laterally extending shoulder portion seated against the upper surface "of said ring with said inwardly folded body portions interposed therebetween, and said unit having a depending flange extending through the inner edge of said ring, said flange being bent outwardly under said ring to clamp said ring against said laterally extending shoulder portion.

2. A collapsible tube comprising, in combination, a cylindricaltubular body, an annular ring, and a premolded shoulder and neck unit, said ring being within said tubular body and having an outside diameter substantially equal to the inside diameter of said tubular body, one end of 45 said tubular body being folded inwardly over and around the inner edge of said ring and outwardly under said ring, said premolded shoulder and neck unit having a laterally extending shoulder portion seated against the upper surface of said ring with said inwardly folded body portions interposed therebetween, and said unit having 9. depending flange extending through the inner edge of said ring, said flangebeing bent outwardly under said ring to clamp the end of said tubular body against said ring and to clamp said ring against said laterally extending shoulder portion. a

3. The method of forming a collapsible tube which comprises placing an annular ring inside one end '01 a cylindrical tubular body, folding the end of said tubular blank over said ring, placing a premolded shoulder and neck over said ring, said shoulder and neck having 2. depending flange extending downwardly inside said ring, and clamping the end of said tubular body between said ring and shoulder by bending said flange outwardly and upwardly under said ring.

4.The method of forming a collapsible tube which comprises placing an annular ring inside one end of a cylindrical tubular body, folding the end of said tubular blank over and around the inner edge of said ring, placing a premolded shoulder and neck over said ring, said shoulder and neck having 9, depending flange extending downwardly inside said ring, and clamping the end of said tubular body between said ring and shoulder and under said ring by bending said flange outwardly and upwardly under said ring.

5. The method of forming avcollapsible tube which comprises placing an annular ring inside one end of a cylindrical tubular body, folding the end of said tubular blank over and around the inner edge of said ring, placing a premolded shoulder and n'eck'over said ring, said shoulder and neck being of thermoplastic material having a depending flange extending downwardly inside said ring, and clamping the end of said tubular body to said ring by applyin heat and pressure to bend said flange outwardly and upwardly under said ring.

ROBERT K. OSTRANDER. 

